Trifluoroacetic acid → 2-Methyl-4-p-tolyl-2,7-diazaspiro[4.5]decan-1-one

To a stirred solution of tert-butyl 2-methyl-1-oxo-4-p-tolyl-2,7-diazaspiro[4.5]decane-7-carboxylate (270 mg, 0.753 mmol) in DCM (5 ml) at 5° C. was added TFA (870 ul, 11.30 mmol) and the reaction mixture was left to stir at 5-10° C. for 1 hr. The reaction mixture was added to 2M NaOH (5 ml) and extracted with DCM (3×5 ml). The organics were combined, washed with brine (5 ml), dried (MgSO4) and concentrated to give the crude product as a white solid (176 mg).